RESUMEN
Human exposure to persistent organic pollutants (POPs) begins during pregnancy and may cause adverse health effects in the fetus or later in life. The present study aimed to assess prenatal POPs exposure to Tanzanian infants and evaluate the distribution of POPs between breast milk, maternal blood, placenta and cord blood. For assessment of prenatal exposure, 48 maternal blood samples from Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), brominated flame retardants (BFRs), dioxin-like (DL) activity and perfluorinated alkyl substances (PFASs). For evaluation of POPs distribution between maternal/infant compartments, breast milk, placenta and cord blood corresponding to the maternal blood were analyzed for OCPs, PCBs and BFRs. In maternal blood, p,p´- DDE was detected in 100% of the samples ranging between 29 and 1890â¯ng/g lipid weight (lw). PCB-153 was the only PCB detected in maternal blood, with detection rate of 29% and concentrations up to 116â¯ng/g lw. BDE-47 was detected in 65% of the maternal blood samples, ranging between Asunto(s)
Contaminantes Ambientales/metabolismo
, Leche Humana/metabolismo
, Efectos Tardíos de la Exposición Prenatal/epidemiología
, Monitoreo del Ambiente
, Familia
, Femenino
, Sangre Fetal
, Humanos
, Lactante
, Kenia
, Exposición Materna/estadística & datos numéricos
, Placenta
, Bifenilos Policlorados/metabolismo
, Embarazo
, Tanzanía/epidemiología
RESUMEN
This is the first study to report organochlorines (OCs), including chlorinated pesticides (OCPs) and polychlorinated biphenyls (PCBs) in human milk from Tanzania. The main aims of this study were to assess the level of contamination and the possible health risks related to OC exposure in nursing infants from the Northern parts of Tanzania. Ninety-five healthy mother-infant couples attending Mount Meru Regional Referral Hospital (MMRRH), Arusha, Tanzania, were assessed for associations between maternal/infant characteristics, i.e. mother's age, BMI, gestational weight gain, occupation, residence and fetal growth parameters and breast milk levels of OCPs, such as dichlorodiphenyltrichloroethane (DDT) and its metabolites, dieldrin and PCBs. p,p'-DDE and p,p'-DDT were detected in 100% and 75% of the breast milk samples, respectively, and ranged between 24 and 2400ng/g lipid weight (lw) and Asunto(s)
DDT/análisis
, Diclorodifenil Dicloroetileno/análisis
, Exposición a Riesgos Ambientales/análisis
, Hidrocarburos Clorados/análisis
, Exposición Materna
, Leche Humana/química
, Plaguicidas/análisis
, Adulto
, Lactancia Materna
, Monitoreo del Ambiente
, Contaminantes Ambientales/análisis
, Femenino
, Humanos
, Lactante
, Salud del Lactante
, Kenia
, Bifenilos Policlorados/análisis
, Embarazo
, Medición de Riesgo
, Tanzanía
, Adulto Joven
RESUMEN
The main aim of this study was to assess brominated flame retardants (BFRs) in breast milk in the Northern parts of Tanzania. Ninety-five colostrum samples from healthy, primiparous mothers at Mount Meru Regional Referral Hospital (MMRRH), Arusha Tanzania, were analyzed for polybrominated diphenyl ethers (PBDEs), hexabromocyclododecane (HBCD), 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE), hexabromobenzene (HBB), (2,3-dibromopropyl) (2,4,6-tribromophenyl) ether (DPTE), pentabromoethylbenzene (PBEB) and 2,3,4,5,6-pentabromotoluene (PBT). The Æ©7PBDE (BDE 28, 47, 99, 100, 153, 154, 183) ranged from below level of detection (Asunto(s)
Lactancia Materna
, Retardadores de Llama/análisis
, Éteres Difenilos Halogenados/análisis
, Leche Humana/química
, Femenino
, Humanos
, Lactante
, Exposición Materna/efectos adversos
, Riesgo
, Tanzanía
RESUMEN
BACKGROUND: Endotoxin exposure may be followed by visceral hypersensitvity but potential mechanisms are not fully explored. We aimed to test the hypothesis that mast cells and the cyclooxygenase pathway (COX) mediate modulation of afferent nerve sensitivity following systemic endotoxin. METHODS: C57Bl6 mice received endotoxin injection i.p. to induce systemic inflammation. Control animals received normal saline. Extracellular multi-unit afferent nerve discharge was recorded from jejunal mesenteric nerves in vitro. Afferent nerve response to 5-hydroxytryptamine (5-HT, 250 µmol/L), bradykinin (BK, 0.5 µmol/L), and to mechanical ramp distension of the intestinal lumen from 0 to 60 cmH2O were recorded 2 h following endotoxin administration. KEY RESULTS: Following endotoxin administration peak afferent discharge to 5-HT and BK was increased compared to controls (p < 0.05). Pre-perfusion with the mast cell stabilizer Doxantrazole (10(-4) M), or the cyclooxygenase inhibitor Naproxen inhibited the increased response to 5-HT and BK (p < 0.05 vs endotoxin pretreatment). Mechanosensitivity during luminal ramp distension from 10 to 60 cmH2O was increased following endotoxin pretreatment compared to controls (p < 0.05). This increase in sensitivity following endotoxin was no longer observed after Doxantrazole or Naproxen administration for pressures from 10 to 30 cmH2O (p < 0.05). Selective COX-2 inhibition by NS398 (10 µM) but not COX-1 inhibition by SC560 (300 µM) reduced increased afferent discharge in endotoxin pretreated animals to 5-HT, BK and mechanical ramp distension from 10 to 40 cmH2O (all p < 0.05). CONCLUSIONS & INFERENCES: Systemic endotoxin sensitizes mesenteric afferent nerve fibers to 5-HT, BK and mechanical stimuli. The underlying mechanism responsible for this sensitization seems to involve mast cells and the COX-2 pathway.
Asunto(s)
Inflamación/metabolismo , Yeyuno/inervación , Yeyuno/fisiología , Lipopolisacáridos/administración & dosificación , Vías Aferentes/efectos de los fármacos , Vías Aferentes/fisiología , Animales , Bradiquinina/farmacología , Inhibidores de la Ciclooxigenasa/farmacología , Yeyuno/efectos de los fármacos , Masculino , Mastocitos/efectos de los fármacos , Mastocitos/fisiología , Ratones , Ratones Endogámicos C57BL , Estimulación Física , Prostaglandina-Endoperóxido Sintasas/metabolismo , Serotonina/farmacología , Tioxantenos/farmacología , Xantonas/farmacologíaRESUMEN
BACKGROUND: Our aim was to explore unknown changes in neurotransmission with vasoactive intestinal peptide (VIP) and Substance P (Sub P) during postoperative ileus (POI). METHODS: Contractile activity of rat circular jejunal muscle strips was studied in five groups (n = 6/group): Naïve controls, sham controls 12 h and 3 days after laparotomy, and rats 12 h, 3 days after induction of POI. Dose-responses to VIP (10(-10) -10(-7) M), Sub P (3 × 10(-10) -3 × 10(-7) M), and electrical field stimulation (EFS, to study endogenous release of neurotransmitters) were studied with different antagonists. Intestinal transit, inflammatory cells and immunoreactivity for VIP and Sub P were investigated in the bowel wall and cellular Finkel osteo sarcoma expression was determined in vagal afferent and efferent nuclei of the brainstem. KEY RESULTS: Postoperative ileus characterized by delayed intestinal transit and intramural inflammation was associated with an increased inhibitory effect of VIP on contractile activity. A biphasic impact was observed for Sub P with a decrease in its excitatory potential on contractility at 12 h, followed by a later increase 3 days postoperatively. Inhibitory response to EFS was increased, whereas the excitatory response decreased in ileus animals. VIP expression was increased in all postoperative animals while only animals 3 days after ileus induction showed increased Sub P expression in the myenteric plexus. These changes were associated with an activation of afferent but not efferent vagal nuclei in the brain stem. CONCLUSIONS & INFERENCES: Specific, time-dependent changes in peptidergic neurotransmission with VIP and Sub P occur during POI that are associated with vagal afferent activation, but are independent of the activation of efferent vagal pathways.
Asunto(s)
Fármacos Gastrointestinales/farmacología , Ileus/etiología , Ileus/fisiopatología , Yeyuno/fisiopatología , Complicaciones Posoperatorias , Sustancia P/farmacología , Péptido Intestinal Vasoactivo/farmacología , Animales , Estimulación Eléctrica , Fármacos Gastrointestinales/metabolismo , Motilidad Gastrointestinal/efectos de los fármacos , Yeyuno/efectos de los fármacos , Masculino , Plexo Mientérico/metabolismo , Ratas , Ratas Sprague-Dawley , Sustancia P/metabolismo , Péptido Intestinal Vasoactivo/metabolismoRESUMEN
INTRODUCTION: Intestinal inflammation alters colonic afferent nerve sensitivity which may contribute to patients' perception of abdominal discomfort. We aimed to explore whether mast cells and the cyclooxygenase pathway are involved in altered afferent nerve sensitivity during colitis. METHODS: C57Bl6 mice received 3% dextran-sulfate sodium (DSS) in drinking water for 7 days to induce colitis. Control animals received regular water. On day 8 inflammation was assessed in the proximal colon by morphology and histology. Extracellular afferent nerve discharge was recorded from the mesenteric nerve of a 2 cm colonic segment. Subgroups were treated in vitro with the mast cell stabilizer doxantrazole (10â»4M) or the cyclooxygenase inhibitor naproxen (10â»5M). RESULTS: DSS colitis resulted in morphological and histological signs of inflammation. At baseline, peak firing was 11±2 imp s⻹ in colitis segments and 5±1 imp s⻹ in uninflamed control segments (p<0.05; mean ± SEM; each n=6). In colitis segments, afferent nerve discharge to bradykinin (0.5 µM) was increased to 47±7 compared to 23±6 imp s⻹ in recordings from non-inflamed control tissue (p<0.05). Mechanosensitivity during luminal ramp distension (0-80 cm H2O) was increased reaching 24±5 imp s⻹ at 80 cm H2O during colitis compared to 14±2 in non-inflamed controls (p<0.05). Doxantrazole or naproxen reduced afferent discharge to bradykinin and luminal ramp distension in colitis segments to control levels. CONCLUSION: Intestinal inflammation sensitizes mesenteric afferent nerve fibers to bradykinin and mechanical stimuli. The underlying mechanism responsible for this sensitization seems to involve mast cells and prostaglandins.
Asunto(s)
Colitis/tratamiento farmacológico , Colon/efectos de los fármacos , Inhibidores de la Ciclooxigenasa/farmacología , Modelos Animales de Enfermedad , Mastocitos/efectos de los fármacos , Neuronas Aferentes/efectos de los fármacos , Prostaglandina-Endoperóxido Sintasas/metabolismo , Inhibidores de la Enzima Convertidora de Angiotensina/farmacología , Animales , Antiinflamatorios no Esteroideos/farmacología , Bradiquinina/metabolismo , Colitis/inmunología , Colitis/metabolismo , Colitis/patología , Colon/inmunología , Colon/inervación , Colon/patología , Técnicas In Vitro , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/inmunología , Mucosa Intestinal/inervación , Mucosa Intestinal/patología , Masculino , Mastocitos/inmunología , Mastocitos/metabolismo , Mastocitos/patología , Mecanotransducción Celular/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Neuronas Aferentes/inmunología , Neuronas Aferentes/metabolismo , Neuronas Aferentes/patología , Inhibidores de Fosfodiesterasa/farmacología , Prostaglandina-Endoperóxido Sintasas/química , Potenciales Sinápticos/efectos de los fármacos , Transmisión Sináptica/efectos de los fármacos , Aferentes Viscerales/efectos de los fármacosRESUMEN
BACKGROUND: To explore postoperative changes in ß-adrenergic neurotransmission that participate in pathophysiology of postoperative ileus. METHODS: Contractile activity of circular jejunal muscle strips was studied. Groups (n = 6/group) were: naïve controls, sham controls 1 and 7 days after laparotomy, and rats 12 h, 1, 3, and 7 days after laparotomy with standardized small bowel manipulation (postoperative ileus). Dose-responses to the ß-agonist isoprenaline (3 × 10(-10) - 10(-7) mol L(-1)) were studied in presence/absence of tetrodotoxin (global neural blockade; 10(-6) mol L(-1) ), N6-(1-iminoethyl)-l-lysine (inhibition of inducible nitric oxide synthesis; 10(-4) mol L(-1)), nimesulide (cyclooxygenase-2 inhibition; 10(-5) mol L(-1)), or propranolol (ß-blockade; 5 × 10(-6) mol L(-1)). Histochemistry for inflammatory cells and intestinal transit were studied. KEY RESULTS: Intramural inflammation and delayed transit (postoperative ileus) occurred only in ileus groups. The inhibitory potential of isoprenaline decreased in all postoperative groups including sham (P < 0.05). Tetrodotoxin enhanced isoprenaline-induced inhibition in ileus and sham groups (P < 0.05). N6-(1-iminoethyl)-l-lysine and nimesulide decreased isoprenaline-induced inhibition in ileus groups 12 h, 1, and 7 days, and in sham controls 7 days postoperatively (P < 0.05). Propranolol prevented isoprenaline effects in all groups (P < 0.05). CONCLUSIONS & INFERENCES: Inhibitory effects of isoprenaline on contractile activity were decreased for 7 days postoperatively. Changes in ß-adrenergic neurotransmission do not induce postoperative ileus and appear to be caused by anesthesia and laparotomy rather than bowel manipulation.
Asunto(s)
Ileus/etiología , Yeyuno/metabolismo , Músculo Liso/metabolismo , Receptores Adrenérgicos beta/metabolismo , Animales , Motilidad Gastrointestinal/fisiología , Ileus/metabolismo , Inmunohistoquímica , Masculino , Contracción Muscular/fisiología , Complicaciones Posoperatorias/etiología , Complicaciones Posoperatorias/metabolismo , Ratas , Ratas Sprague-Dawley , Transmisión SinápticaRESUMEN
The evolution of crop-related weeds may be constrained by recurrent gene flow from the crop. However, flowering time variation within weedy populations may open the way for weed adaptation by allowing some weeds to escape from this constraint. We investigated this link between phenology, gene flow and adaptation in weedy sunflower populations that have recently emerged in Europe from crop-wild hybridization. We studied jointly flowering phenology and genetic diversity for 15 microsatellite loci in six cultivated sunflower (Helianthus annuus) fields infested by weedy sunflower populations. The flowering overlap of cultivated and weedy sunflowers varied between and within populations: some weedy individuals were found to be completely isolated from the crop, the frequency of these plants being higher in populations from highly infested fields. Within weedy populations, we detected a pattern of isolation-by-time: the genetic divergence between individuals was positively correlated with their divergence in flowering period. In addition, earlier weeds, which flowered synchronously with the crop, were genetically more similar than late-flowering weeds to the cultivated varieties. Overall, our results suggest that crop-to-weed gene flow occurred, but was limited by divergent phenologies. We discuss the roles of weed adaptation and population history in the generation of this partial reproductive isolation.
Asunto(s)
Productos Agrícolas/genética , Flores/fisiología , Flujo Génico/genética , Helianthus/genética , Helianthus/fisiología , Malezas/genética , Bases de Datos como Asunto , Variación Genética , Genética de Población , Filogenia , Factores de TiempoRESUMEN
The results of cytogenetic and molecular cytogenetic investigations revealed similarities in genetic background and biological behaviour between tumours and genetic diseases of humans and dogs. These findings classify the dog a good and accepted model for human cancers such as osteosarcomas, mammary carcinomas, oral melanomas and others. With the appearance of new studies and advances in canine genome sequencing, the number of known homologies in diseases between these species raised and still is expected to increase. In this context, array-based comparative genomic hybridization (aCGH) provides a novel tool to rapidly characterize numerical aberrations in canine tumours or to detect copy number aberrations between different breeds. As it is possible to spot probes covering the whole genome on each chip to discover copy number aberrations of all chromosomes simultaneously, this method is time-saving and cost-effective - considering the relation of costs and the amount of data obtained. Complemented with traditional methods like karyotyping and fluorescence in situ hybridization (FISH) analyses, the aCGH is able to provide new insights into the underlying causes of canine carcinogenesis.
Asunto(s)
Hibridación Genómica Comparativa/veterinaria , Enfermedades de los Perros/genética , Neoplasias/veterinaria , Animales , Análisis Citogenético/veterinaria , Modelos Animales de Enfermedad , Perros , Neoplasias/genéticaRESUMEN
During the last years attempts have been made to draw lessons from aviation to increase patient safety in medicine. In particular similar conditions are present in surgery as pilots and surgeons may have to support high physical and mental pressure. The use of a few safety instruments from aviation is feasible in an attempt to increase safety in surgery. First a "root caused" accident research may be established. This is achievable by morbidity and mortality conferences and critical incident reporting systems (CIRS). Second, standard operating procedures may assure a uniform mental model of team members. Furthermore, crew resource management illustrates a strategy and attitude concept, which is applicable in all situations. Safety instruments from aviation, therefore, seem to have a high potential to increase safety in surgery when properly employed.
Asunto(s)
Medicina Aeroespacial/educación , Medicina Aeroespacial/normas , Cirugía General/educación , Cirugía General/normas , Errores Médicos/prevención & control , Seguridad del Paciente/normas , Prevención de Accidentes , Causalidad , Conducta Cooperativa , Curriculum , Predicción , Alemania , Humanos , Capacitación en Servicio , Comunicación Interdisciplinaria , Asignación de Recursos , Estrés Psicológico/complicaciones , Análisis y Desempeño de TareasRESUMEN
Cultivated plants have been molded by human-induced selection, including manipulations of the mating system in the twentieth century. How these manipulations have affected realized parameters of the mating system in freely evolving cultivated populations is of interest for optimizing the management of breeding populations, predicting the fate of escaped populations and providing material for experimental evolution studies. To produce modern varieties of sunflower (Helianthus annuus L.), self-incompatibility has been broken, recurrent generations of selfing have been performed and male sterility has been introduced. Populations deriving from hybrid-F1 varieties are gynodioecious because of the segregation of a nuclear restorer of male fertility. Using both phenotypic and genotypic data at 11 microsatellite loci, we analyzed the consanguinity status of plants of the first three generations of such a population and estimated parameters related to the mating system. We showed that the resource reallocation to seed in male-sterile individuals was not significant, that inbreeding depression on seed production averaged 15-20% and that cultivated sunflower had acquired a mixed-mating system, with â¼50% of selfing among the hermaphrodites. According to theoretical models, the female advantage and the inbreeding depression at the seed production stage were too low to allow the persistence of male sterility. We discuss our methods of parameter estimation and the potential of such study system in evolutionary biology.
Asunto(s)
Cruzamiento/métodos , Helianthus/genética , Hibridación Genética , Endogamia , Fenotipo , Autoincompatibilidad en las Plantas con Flores/genética , Análisis de Varianza , Genotipo , Repeticiones de Microsatélite/genética , Reproducción/fisiología , Semillas/crecimiento & desarrollo , Factores SexualesAsunto(s)
Neoplasias del Recto/cirugía , Recto/cirugía , Terapia Combinada , Incontinencia Fecal/prevención & control , Humanos , Terapia Neoadyuvante , Invasividad Neoplásica , Estadificación de Neoplasias , Complicaciones Posoperatorias/prevención & control , Proctocolectomía Restauradora , Pronóstico , Neoplasias del Recto/tratamiento farmacológico , Neoplasias del Recto/patología , Neoplasias del Recto/radioterapia , Recto/patología , Prevención SecundariaRESUMEN
Volunteers deriving from unharvested seeds of a crop can lead to persistent feral populations and participate in genetic exchanges across the agro-ecosystem, both between crop varieties and between crops and their wild relatives. A first step to understand the importance of volunteers is to characterize their capacity to reproduce autonomously for several generations. For that purpose, we constructed and evaluated a maximum-likelihood method to estimate the genetic age of a population deriving from one of the most common field crop type: an F1-hybrid variety. The method estimates the number of reproduction cycles that occurred since the cultivation of that variety. It makes use of genotypic data at a number of linked microsatellite loci pairs, thus exploiting the recombination of parental haplotypes, which is expected to occur as the population is reproducing. Estimates with moderate bias and variance were found for a broad range of parameter values in simulations, and the method revealed robust to some deviations from the assumptions of the underlying model. We propose a specific procedure to test the hypothesis of persistence, that is has a given volunteer population experienced more than one cycle of reproduction since the F1-hybrid state? The method was applied to both an experimental and a natural sunflower volunteer population and revealed promising, considering these ideal case studies. Possible further developments toward more complex natural systems are discussed.
Asunto(s)
Productos Agrícolas/genética , Marcadores Genéticos , Genética de Población/métodos , Estadística como Asunto/métodos , Simulación por Computador , Investigación Empírica , Flujo Génico , Frecuencia de los Genes , Ligamiento Genético , Marcadores Genéticos/fisiología , Especiación Genética , Genética de Población/estadística & datos numéricos , Helianthus/genética , Funciones de Verosimilitud , Modelos Teóricos , Factores de TiempoRESUMEN
Evidence exists that visceral afferent sensitivity is subject to regulatory mechanisms. We hypothesized that afferent sensitivity is decreased in the small intestine during intestinal inflammation by an inducible nitric oxide synthase (iNOS)-dependent mechanism. C57BL/6 mice were injected twice with vehicle or 60 mg kg(-1) indomethacin subcutaneously to induce intestinal inflammation. Afferent sensitivity was recorded on day 3 from a 2-cm segment of jejunum in vitro by extracellular multi-unit afferent recordings from the mesenteric nerve bundle. In subgroups (n = 6), iNOS was inhibited selectively by L-N6-(1-iminoethyl)-lysine (L-NIL) given either chronically from day 1-3 (3 mg kg(-1) twice daily i.p.) or acutely into the organ bath (30 micromol L(-1)). The indomethacin-induced increase of macroscopic and microscopic scores of intestinal inflammation (both P < 0.05) were unchanged after pretreatment with L-NIL. Peak afferent firing following bradykinin (0.5 micromol L(-1)) was 55 +/- 8 impulse s(-1) during inflammation vs 97 +/- 7 impulse s(-1) in controls (P < 0.05). Normal firing rate was preserved following L-NIL pretreatment (112 +/- 16 impulse s(-1)) or acute administration of L-NIL (108 +/- 14 impulse s(-1)). A similar L-NIL dependent reduction was observed for 5-HT (250 micromol L(-1)) and mechanical ramp distension from 20 to 60 cmH(2)O (both P < 0.05). Intraluminal pressure peaks were decreased to 0.66 +/- 0.1 cmH(2)O during inflammation compared to 2.51 +/- 0.3 in controls (P < 0.01). Afferent sensitivity is decreased by an iNOS-dependent mechanism during intestinal inflammation which appears to be independent of the inflammatory response. This suggests that iNOS-dependent nitric oxide production alters afferent sensitivity during inflammation by interfering with signal transduction to afferent nerves rather than by attenuating intestinal inflammation.
Asunto(s)
Antiinflamatorios no Esteroideos/farmacología , Indometacina/farmacología , Inflamación/inducido químicamente , Yeyuno , Neuronas Aferentes/fisiología , Óxido Nítrico Sintasa de Tipo II/metabolismo , Animales , Bradiquinina/farmacología , Electrofisiología , Humanos , Inflamación/patología , Yeyuno/efectos de los fármacos , Yeyuno/inervación , Yeyuno/patología , Lisina/análogos & derivados , Lisina/farmacología , Masculino , Ratones , Ratones Endogámicos C57BL , Neuronas Aferentes/efectos de los fármacos , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Serotonina/farmacologíaRESUMEN
The perennial outcrossing Arabidopsis lyrata is becoming a plant model species for molecular ecology and evolution. However, its evolutionary history, and especially the impact of the climatic oscillations of the Pleistocene on its genetic diversity and population structure, is not well known. We analyzed the broad-scale population structure of the species based on microsatellite variation at 22 loci. A wide sample in Europe revealed that glaciations and postglacial colonization have caused high divergence and high variation in variability between populations. Colonization from Central Europe to Iceland and Scandinavia was associated with a strong decrease of genetic diversity from South to North. On the other hand, the Russian population included in our data set may originate from a different refugium probably located more to the East. These genome-wide patterns must be taken into account in studies aiming at elucidating the genetic basis of local adaptation. As shown by sequence data, most of the loci used in this study do not evolve like typical microsatellite loci and show variable levels of homoplasy: this mode of evolution makes these markers less suitable to investigate the between-continent divergence and more generally the worldwide evolution of the species. Finally, a strong negative correlation was detected between levels of within-population diversity and indices of differentiation such as F(ST). We discuss the causes of this correlation as well as the potential bias it induces on the quantification and interpretation of population structure.
Asunto(s)
Arabidopsis/genética , Cubierta de Hielo , Arabidopsis/clasificación , Secuencia de Bases , Evolución Biológica , Europa (Continente) , Variación Genética , Genética de Población , Genoma de Planta , Funciones de Verosimilitud , Desequilibrio de Ligamiento , Repeticiones de Microsatélite/genética , Datos de Secuencia Molecular , Mutación , Alineación de Secuencia , Análisis de Secuencia de ADNRESUMEN
INTRODUCTION: A limited number of drugs are available for the treatment of functional dyspepsia and irritable bowel syndrome. The efficacy of STW 5 (Iberogast) was previously shown in clinical trials. Since visceral hypersensitivity seems to be the prime pathomechanism of functional gastro-intestinal disorders, the aim of this study was to explore whether STW 5 reduces intestinal afferent sensitivity in the upper gastrointestinal tract. METHODS: Two groups of male Wistar rats were pretreated with either the herbal preparation STW 5 or its vehicle (30.8% ethanol). Then, after 2h, general anesthesia was induced by pentobarbitone (60 mg kg(-1)i.p.) and extracellular multi-unit afferent recordings were obtained from mesenteric afferents innervating the proximal jejunum. The intestinal afferent nerve response to increasing doses of 5-HT and bradykinin were quantified as well as afferent discharge following a ramp distension of the adjacent intestinal loop from 0 to 60 cm H(2)O. RESULTS: Afferent discharge to 5-HT and bradykinin increased dose-dependently. Following the different doses of 5-HT, the peak in afferent nerve discharge was always reduced after pretreatment with STW 5 compared to controls with a response of 110+/-5 imp s(-1) after STW 5 and 128+/-3 in vehicle controls at the maximum dose (40 microg kg(-1); p<0.05; mean+/-SEM). For bradykinin, afferent responses were reduced following STW 5 at the 20 and 40 microg kg(-1) dose but not at 10 microg kg(-1) (40 microg kg(-1)176+/-7 imp s(-1) following STW 5 versus 200+/-6 imp s(-1) in controls; p<0.05). The ramp distension of the intestinal loop stimulated a rise in intestinal afferent nerve discharge that was always lower in the STW 5 pretreated group compared to vehicle controls with the exception of the discharge rate at the pressure level of 0 and 20 cm H(2)O (all other pressures up to 60 cm H(2)O p<0.05). CONCLUSIONS: Sensitivity of intestinal afferents to mechanical and chemical stimuli is reduced following treatment with the herbal preparation STW 5. This mechanism may help to explain why STW 5 relieves dyspeptic and bowel symptoms in patients.
Asunto(s)
Fármacos Gastrointestinales/farmacología , Intestino Delgado/efectos de los fármacos , Intestino Delgado/inervación , Neuronas Aferentes/efectos de los fármacos , Extractos Vegetales/farmacología , Vías Aferentes/efectos de los fármacos , Animales , Bradiquinina/farmacología , Masculino , Ratas , Ratas Wistar , Serotonina/farmacología , Estrés MecánicoRESUMEN
DNA sequence polymorphism carries genealogical information and allows for testing hypotheses on selection and population history, especially through coalescent-based analysis. Understanding the evolutionary forces at work in plant domestication and subsequent selection is of critical importance for the management of genetic resources. In this study, we surveyed DNA sequence diversity at two assumed neutral nuclear loci in the wild-domesticated species complex of alfalfa (Medicago sativa L.). A high level of polymorphism was detected. The domesticated pool contains on average 31% less diversity than the wild pool, but with a high heterogeneity among loci. Coalescent simulations of the domestication process showed that this result cannot be explained by assuming a constant population size but is rather consistent with a demographic bottleneck during domestication. A very low level of divergence was detected between the wild and the domesticated forms as well as between the related subspecies of the M. sativa species complex. However, the originality of the Spanish wild populations, already observed based on mitochondrial DNA polymorphism, was confirmed. These results, together with patterns of intrapopulation polymorphism, suggest that nuclear sequence polymorphism could be a promising tool, complementary to mitochondrial DNA and phenotypic evaluations, to investigate historical demographic and evolutionary processes.
Asunto(s)
Medicago sativa/genética , Polimorfismo Genético , Evolución Biológica , Núcleo Celular/genética , Geografía , Haplotipos , Reacción en Cadena de la Polimerasa , Selección GenéticaRESUMEN
BACKGROUNDS AND AIMS: The mechanisms underlying endotoxin-induced hyperalgesia remain unknown. We aimed to study the mechanisms underlying the sensitizing action of lipopolysaccharide (LPS) on intestinal afferent responses to mechanical and chemical stimuli. METHODS: Extracellular recordings of jejunal afferent nerve discharge were obtained from pentobarbitone-anaesthetized rats. RESULTS: Lipopolysaccharide (6 mg kg(-1), i.v.) stimulated a short-term, transient (<30 min) increase in chemosensitivity to systemic 5-HT (6 microg kg(-1)) and responses to mechanical distension and a delayed but maintained (>30 min) increase in spontaneous afferent discharge. Naproxen (10 mg kg(-1)) and the prostaglandin receptor antagonist AH6809 (1 mg kg(-1)) significantly attenuated both the short-term sensitization to mechanical distension and 5-HT and the long-term increase in baseline afferent firing following LPS. In contrast, the iNOS inhibitor aminoguanidine (15 mg kg(-1)) and the L-type calcium channel antagonist nifedipine (1 mg kg(-1)) both prolonged the period of afferent sensitization to distension and 5-HT without influencing the augmented baseline-firing rate. omega-Conotoxin GVIA attenuated the increase in afferent discharge to LPS, without any change in mechano- and chemosensitivity. CONCLUSIONS: The long-term (>30 min) increase in afferent firing following systemic LPS involves neurogenic release of prostanoids. The short-term (<30 min) sensitization also appears to depend on prostanoid release, while nitric oxide production may serve to down-regulate LPS-induced afferent hypersensitivity.
Asunto(s)
Lipopolisacáridos/farmacología , Mesenterio/inervación , Neuronas Aferentes/efectos de los fármacos , Neuronas Aferentes/fisiología , Potenciales de Acción/efectos de los fármacos , Potenciales de Acción/fisiología , Animales , Presión Sanguínea/efectos de los fármacos , Bloqueadores de los Canales de Calcio/farmacología , Inhibidores de la Ciclooxigenasa/farmacología , Guanidinas/farmacología , Hemodinámica/efectos de los fármacos , Masculino , Mesenterio/efectos de los fármacos , Naproxeno/farmacología , Nifedipino/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II , Estimulación Física , Antagonistas de Prostaglandina/farmacología , Prostaglandinas/metabolismo , Ratas , Serotonina/farmacología , Antagonistas de la Serotonina/farmacología , Estimulación Química , Xantonas/farmacología , omega-Conotoxina GVIA/farmacologíaRESUMEN
INTRODUCTION: Visceral hypersensitivity in the upper gastrointestinal tract is a potential pathomechanism of functional dyspepsia. The herbal preparation STW 5 (Iberogast) provides symptomatic relief for this condition. We aimed to investigate whether STW 5 modulates intestinal afferent sensitivity. METHODS: The herbal preparation STW 5 or vehicle (30.8% ethanol) were administered orally in male Wister rats. After 2 h animals were anaesthetized and extracellular multi-unit intestinal afferent nerve recordings were secured from the neurovascular bundle of the mesentery in the proximal jejunum. Afferent discharge to ramp distension of the intestinal loop (0-60 cm H2O) and dose-response curves for i.v. bradykinin (10, 20 and 40 microg kg(-1)) and 5-HT (5, 10, 20 and 40 microg kg(-1)) were recorded. RESULTS: Baseline discharge was not different between the vehicle and treatment group. Ramp distension was followed by a pressure dependent increase in afferent nerve discharge that was decreased following STW 5 pretreatment for all distending pressures reaching 147 +/- 8 impulses s(-1) (imp s(-1)) following STW 5 vs 171 +/- 5 imp s(-1) following vehicle at 60 cm H2O (mean +/- SEM; P < 0.05). A dose-dependent increase in afferent discharge was observed for 5-HT and bradykinin. Following STW 5 pretreatment, afferent discharge was reduced at all doses of 5-HT to 110 +/- 5 at the maximum dose after STW 5 and 128 +/- 3 imp s(-1) in controls (all P < 0.05). Afferent discharge to bradykinin was similarly reduced at 20 and 40 microg kg(-1) but not at 10 microg kg(-1) of bradykinin with a discharge rate of 176 +/- 7 imp s(-1) following STW 5 and 200 +/- 6 imp s(-1) in controls at 40 microg kg(-1) (P < 0.05). CONCLUSIONS: The preparation STW 5 reduces intestinal afferent nerve discharge following chemical and mechanical stimuli, while baseline discharge is not affected. This effect of STW 5 on afferent sensitivity may contribute to its therapeutic relief of dyspeptic symptoms.
Asunto(s)
Intestino Delgado/efectos de los fármacos , Intestino Delgado/inervación , Neuronas Aferentes/efectos de los fármacos , Neuronas Aferentes/fisiología , Extractos Vegetales/farmacología , Animales , Masculino , Ratas , Ratas WistarRESUMEN
SETTING: Few series of paediatric tuberculosis (TB) have been reported in the last 20 years. OBJECTIVE: To describe diagnostic and treatment practices in children with TB living in Seine-Saint-Denis, a low-income Paris suburb. METHODS: Local TB incidence in 1998 was 34.2/100,000 overall and 10.2/100,000 in children. Between September 1996 and December 1997, the hospitals and prevention units serving the area's paediatric population were sent questionnaires to identify TB cases in children aged under 15 living in Seine-Saint-Denis and treated with at least one anti-tuberculosis drug. RESULTS: Of 92 cases identified, 60 (65%) had been diagnosed during contact tracing; for 52 patients (60%), the index case had been found. The reason for anti-tuberculosis treatment was active TB in 26 (28.3%), latent TB in 46 (50%), and prophylaxis in 20 (21.8%). Forty per cent (37/92) of the patients were aged under 5. Only 15 of the 35 notified cases met the criteria for mandatory notification (at least three anti-tuberculosis drugs). CONCLUSION: TB remains a public health problem in Seine-Saint-Denis. The high proportion of cases identified by contact tracing attests to the efficacy of the local contact-tracing programme. The criteria for mandatory notification in France were too restrictive to ensure effective surveillance of childhood TB. Since 2002, notification has included cases of tuberculous infection in children.